Vacuum bulb mounting



Julie 1932- A. 1. CRAWFORD ETAL 1,864,528

VACUUM BULB MOUNTING Filed Jan. 21. 1950 A CRAWFORD //v VENTORS 5. GLAss ATTORNEY Patented June 28, 1932 UNITED STATES PATENT OFFICE ALLEN I. CRAWFORD, OF NEW YORK, N. Y., AND MYRON S. GLASS, OF EAST ORANGE,

NEW JERSEY, ASSIGNORS TO BELL TELEPHONE LABORATORIES, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK VACUUM BULB MOUNTING Application filed January 27, 1930. Serial No. 423,628;

ed casing and member which are cemented together, and cooperating means thereon whereby relative lateral turning of the casmg and base member is prevented, a shoulder portion on-the base member which limits the longitudinal traverse of the base member within the casing to a fraction of its length and the combination of the above features which permits ready separation of the casing and base member when required.

In the accompanying drawing Fig. 1 is an exploded view, of the mounting or thermocouple enclosure; Fig. 2 isa side elevation partly in section showing the mounting with a vacuum thermocouple therein; and Fig. 3 is an end view of the closed end of the mount- 1n %n vacuum bulb devices and particularly those of the thermocouple type in which extraneous shocks and changes in temperature in the atmospher c surrounding the vacuum bulb affect the operation or performance of the electrodes or elements contained within the blllbflt is found advantageous to enclose the vacuum bulb in material which will protect the bulb and the elements contained therein against the' efiects of outside temperature changes or extraneousshocks. Cotton batting coverings and metal enclosure members have already been provided for this purpose, but the enclosure members being made of metal tubing are not in themselves good insulators against temperature changes and having end closure members which have 7 to be pinned therein or secured by screws or the like are of comparatively expensive construction. Removal of the end closure member from the tubular casing for the purpose of replacing the vacuum bulb is also rather diflicult in these known structures.

To provide an enclosure member having plug 7 and casing 1.

in itself good temperature insulating qualities, it is proposed in this invention to make the casing of a material which is not readily responsive to changes in temperature. It is also proposed to mold these casings to reduce the cost of production, and to facilitate replacement of the vacuum bulbs enclosed in the casings the end closing members instead of being secured in the casings by screws or thelike are cemented. Other novel features residing in the structure proposed will be apparent from a study of the accompanying drawing in which 1 is a molded casing of bakelite or like material having a closed end 2 and an open end 3. Across the outer face 1 a vacuum bulb socket projects from the outer surface of the casing 1 and is positioned in a longitudinal line projected from the moldedin slot 5.

To close the open end of the casing 1 and to provide means by which the leads from the elements contained in a vacuum bulb may be brought into electrical connection with suitable terminals in a socket, a molded plug 7 of insulating material with suitable electrical terminal members 8 therein is provided.

On the molded plug 7 is an extended andreduced portion 9 adapted to fit within the open end 3 of the casing 1. A shoulder portion 10 is also provided on the plug 7 to engage and seat against the rim of the open end ot the casing and prevent the plug 7 from being pushed too far within the casing. Molded onto the shoulder 10 is a lug 11 which when the plug 7 is inserted in the open end 3 of the casing fits into the molded-in slot 5 and prevents relative lateral turning of the The terminal members 8 herein are shown as pin type terminals having shoulder portions 12 as shown in Fig. 2 to engage the outer face of the plug 7. These terminal members 8 are drilled from their upper ends and the drill hole in each terminal emerges at a point 13 just below the shoulder portion 12. The terminal members- 24 of the plug 7 to secure them in place.

In Fig. 2 a vacuum bulb 15 wrapped in cotton batting or like material 16 is shown as enclosed in the casing. The lead-in wires 17 leading to the elements within the bulb and extending outward from a reentrantportion 18 of the bulb are threaded through the drill holes in the terminal members 8 and secured by solder at the points 13 where the drill holes emerge below the shoulder portions 12. The plug 7 is cemented at 19 to the open end 3 of the casing 1, the cement also extending into the slot 5 in the casing and around the lug 11 of the plug as shown at 20.

The slot lwhich is molded into the closed end 2 of the casing 1 is provided to accommodate a bar 21 which is secured therein by a pin or screw 22 and serves as a means by which the top of the casing may be secured to screws or the like in a wall of a cabinet housing the casing and associated apparatus. Slots 23 are provided in the bar 21 by which it may be hooked under the screw heads.

In placing the vacuum bulb in the casing the usual procedure is to first attach the leadin wires 17 to the terminals 8 of the plug 7, wrap the vacuum bulb 15 in cotton batting or the like, coat the open end 3 of the casing 1 and the extended portion 9 and shoulder 10 of the plug 7 with cement and insert the,

wrapped vacuum bulb and the plug 7 in the casing so that the lug 11 on the plug 7 fits into the slot 5 of the casing.

With the plug 7 cemented to the open end 3 of the casing 1 and the lug 11 engaging thew slot 5, relative lateral turning of the plug 7 and easing, such aswould cause crossing of the lead-in wires 17 is prevented.

To replace the vacuum bulb 15 by another, the cement between the plug 7 and casing 1 may be heated or dissolved, the plug 7 and vacuum bulb 15 withdrawn from the casing and the bulb 15 separated from the terminals 8 by melting the solder from the lead-in wires 17 and terminals 8.

What is claimed is:

1. A vacuum bulb unit comprising an evacuated vessel having electrodes therein and lead-in wires extending outward of said vessel from the electrodes, a cup-shaped casing of heat insulating material enclosing said vessel, a plug member of heat insulating material to close the open end of said casing, electrical terminals connected to said leadin wires and projecting from said plug member, and a peripherally disposed lug on said lug member coo crating with side walls -orming a slot in t e open end of said casing to prevent relative axial turning movements of said plug and casing and crossing of said lead-in wires when the evacuated vessel is inserted within said casing.

2. A vauum bulb unit comprising a cupshaped easing offheat insulating material, a vacuum bulb containing electrodes enclosed in said'casing, heat insulating and shock absorbing material disposed around said vacuum bulb within the casing, a plug of heat insulating material for the open end of said ments of the plug and easing as would cause crossing of the lead-in wires when the plug is inserted in the casing.

3. A thermocouple unit comprising a vacuum thermocouple, a cup-shaped casing of heat insulating material enclosing said thermocouple, heat insulating and shock absorbing material wrapped around said thermocouple within said casing, a plugof heat said casing, electrical terminals supported in said plug, lead-in WlI'BS' connecting said thermocouple and said terminals, said plug having an annular shoulder engaging the rim of the casing to limit to a fraction of its length insertion of the plug within the casing, and a lug projecting into a slot formed in the wall of the open end of the casing to prevent relative axial turning movements of said plug and easing such as would cause crossing of said lead-in wires when the thermocouple with its attached plug is inserted in the casing.

In witness whereof, we hereunto subscribe our names this 25th day of January, 1930.

' ALLEN I. CRAWFORD.

MYRON S. GLASS.

,insulating material closing an open end of 

